314 J. FOR. SCI., 56, 2010 (7): 314–322 JOURNAL OF FOREST SCIENCE, 56, 2010 (7): 314–322 Stabilization of forest functions is the main objec- tive of the present forest management in mountain areas. Norway spruce (Picea abies [L.] Karst.) has an irreplaceable (stand-forming) function in forest ecosystems at higher mountain locations; therefore it is desirable to assess real potentials of this tree species in order to increase the tolerance of newly established plantations. Development of forest sys- tems at high altitudes is limited by a combination of environmental factors. Besides these natural limita- tions high mountains are especially sensitive to air pollution that can have very negative effects on al- ready damaged forest stands (G et al. 2005). e selection of planting stock genetically best adapted to the given conditions is a crucial issue for reforestation of high-elevation localities (H et al. 1991). One of the possibilities of increasing the stability of future plantations is to use spruce trees with higher stress tolerance. is is the reason why a great attention has been paid to progenies of the most vital spruces from remnants of indigenous stands in the Krkonoše model mountain area. e objective of the present paper is to inform about the results of our research on the use of po- tentially stress-tolerant progenies of Norway spruce in forest regeneration in mountain localities. ese clone mixtures from Norway spruce moun- tain populations were gradually produced in the framework of long-term programmes using the clonal propagation (J et al. 1994); their re- Evaluation of the growth and health status of selected clone mixtures in comparison with ordinary planting stock J. L, A. J, J. M Forestry and Game Management Research Institute, Opočno Research Station, Opočno, Czech Republic ABSTRACT: e present paper compares the growth of parent trees and potentially stress-tolerant mixtures of clones of Norway spruce (Picea abies [L.] Karst.) progenies coming from a specific locality near the Černá hora peat bog in the Krkonoše Mts. Growth was studied in generative ortet plantations in Trutnov locality and in a mountain ortet plantation Lesní bouda, in the 1 st generation clone plantation Benecko and in the 2 nd generation clone plantation in the Černohorská rašelina locality. In the latter locality chlorophyll fluorescence and water losses during controlled desiccation were also measured in selected clones compared to control (generatively propagated) spruces. Partial data acquired until now prove the good growth dynamics and physiological state of some clones in extreme climatic conditions indicating that cuttings were taken from vital parent trees growing in exposed mountain localities. Growth relations among the clones were identical in all evaluated localities. e growth of the 2 nd generation clone plantation has been markedly influenced by plantation and specific site conditions until now. e mutual interaction of clone growth and site conditions can change in time and therefore the study of clone plantations will continue in the years to come. Keywords: chlorophyll fluorescence; clonal propagation; growth; mother plantations; mountain conditions; Norway spruce; water losses Supported by the Ministy of Agriculture of the Czech Republic, Project No. 1G58021. J. FOR. SCI., 56, 2010 (7): 314–322 315 alization started in the eighties, at the time of the culmination of air-pollution disaster. In that period, within the programme of the gene conservation of indigenous forest tree species in the Krkonoše Mts. (S 1996; S, V 1997) relatively tolerant individuals that survived in disintegrating forest stands were selected. Our previous activi- ties (Ministry of Agriculture of the Czech Republic Project MZe QD1274 “Stress-tolerant Clone Mix- tures for Mountain Areas”) in the Krkonoše model mountain area were aimed at the establishment of a series of ortet plantations and clone plantations of spruce coming from indigenous or potentially stress-tolerant trees (J, M 2005). Further selection was done during the collection of cuttings from vital trees in the 1 st generation clone plantation. at means in situ double selection was done in these rooted cuttings of the 2 nd generation. e selection of individuals for further growing was performed on the basis of the complex evaluation of parent trees (the health status was the main crite- rion, and both the individuals with intensive growth dynamics and the slow-growing individuals were selected for a subsequent mixture of clones). After their growing in a nursery they were outplanted in exposed locations where their observation continues and their growth and health status are compared with the ordinary planting stock of generative origin. e objective of these experiments is to evaluate possibilities of natural selection of tolerant clones by situating ortet plantations and clone plantations into extreme mountain conditions. MATERIAL AND METHODS Growth and health status were evaluated in parent trees in generatively established ortet plantations – research plots (RP) in favourable conditions in the Trutnov area (Trutnov RP) and in rather extreme mountainous conditions in the Krkonoše Mts. area (Lesní bouda RP). eir vegetative progenies – clones were evaluated in a clone plantation in the Benecko area and in the 2 nd generation rooted cut- tings (coming from the clone plantation on Benecko RP and outplanted in the extreme mountain locality Černohorská rašelina). A description of the plots is shown in Table 1. We studied the progenies of spruces coming from the area of the Černohorská rašelina locality, i.e. such progenies that were potentially best adapted to specific local conditions. A detailed evaluation was done in the half-sib progeny of tree No. 8 from this locality (designated as cr8). Total number of planting stock outplanted on RP was 900. e clones that had a high number of individuals in all studied localities were selected within this progeny. e evaluation of spruce growth in clone plantations (RP) was based on the measurement of height and diameter growth. Diameter growth in young plantations was assessed by measuring root collar diameters. Shape irregulari- ties, coloration changes and needle loss (defoliation) and potential damage to shoots were recorded at the same time. The physiological state of selected clones was evaluated in a laboratory in samples of branches collected in the 2 nd generation clone plantation on Černohorská rašelina RP. Branches were taken from the 2 nd whorl from above in rooted cuttings and control plants grown by a routine method. e samples were put into a cooling box in the field and subsequently transported to a laboratory for evalua- tion. In the laboratory the branch bases were put into water, covered and sealed with black polyethylene foil in order to maintain high atmospheric humidity and let soak water overnight at a room temperature. On the next day they were exposed to light (covered with transparent foil) minimally for one hour to induce stomatal opening. Parts of annual shoots were then used for the evaluation of water losses. Single needles were taken from the remaining parts of branches to measure chlorophyll fluorescence. Needles were stuck onto cellotape strips on paper pads and before the measurements started, they were let adapt themselves to darkness in moist dark chambers minimally for 30 minutes. After the green dark-adapted tissues were illuminated, the intensity Table 1. Description of research plots (RP) Research plot Type Altitude (m a.s.l.) Years of foundations Lesní bouda ortet mixture 1,080 1989 Trutnov 520 1990 Benecko clone plantation 1 st generation 750 1997 Černohorská rašelina clone plantation 2 nd generation 1,180–1,200 2004 2005 316 J. FOR. SCI., 56, 2010 (7): 314–322 of their fluorescence changed in a typical way in- dicating the state of the photosynthetic apparatus (M et al. 1995). Chlorophyll fluorescence was measured with an Imaging-PAM 2000 device (Heinz Walz GmbH). ree needles from each branch were evaluated. In dark-adapted needle samples the basic character- istics of fluorescence were measured: F o – minimal fluorescence and F m – maximal fluorescence after a strong flash of light; from these variables the maximal quantum yield of fluorescence (F m – F o )/F m designated as F v /F m was computed, representing the maximal photochemical efficiency of photosystem II. is characteristic is used most frequently to assess the state of assimilatory organs (M, J 2000). A more detailed description of the above-mentioned basic variables was published in a number of theoretical papers (e.g. M, J- 2000; L et al. 2005; R, L 2005). Measuring light of the intensity 3 molm –2 s –1 and saturation pulse of the intensity 2,400 molm –2 s –1 with the duration of 800 ms were used for measurements in our laboratory. The ability to resist drought was evaluated by repeated weighing of annual shoots in the course of controlled desiccation in laboratory conditions (S et al. 1965). Water content was expressed as % of the initial water content in saturation state. Data were processed by Excel and QC Expert pro- grammes. Analysis of variance (ANOVA) was used to test the differences due to provenance of clones within in all studied characteristics. Subsequently, paired comparisons of pairs of the clone progenies were done by Scheffé’s test. Ob- served significant differences among the variants are documented in graphs of the particular characteris- tics (different letters show significant differences). RESULTS Comparison of the growth of parent trees and clones of the 1 st and 2 nd generation Research plots were evaluated in the intervals of several years. So data acquired in plantations of dif- ferent age growing in different natural conditions are available. e objective is not to compare the absolute values of reached height or stem diameter but to compare the relations among the clones or to compare the clone stock with ordinary generatively propagated plants. Figs. 1 and 2 illustrate the height and diameter of parent trees in ortet plantations on Lesní bouda and Trutnov RPs 12 years after outplanting. eir evaluation must consider highly different growth conditions in the particular mother plantations (foothill and mountain sites). e presented values are mainly applicable to evaluate their vegetative progenies in clone plantations. e graphs document Fig. 1. Shoot height of parent spruces in generative mother plantations 12 years after outplanting Fig. 2. Stem diameter of parent spruces in generative mother plantations 12 years after outplanting Table 2. Analysis of variance for root collar diameter on Černohorská rašelina RP Sums of squares Degrees of freedom Mean squares F exp Variants (clones) Sa = 809.5 6 6,613 25,536 Error Sr = 3,032.6 574 5,229 Total Sc = 3,842.0 580 Conclusion of test: effect is statistically significant at the α = 0.05 level 60 70 ) Lesní Bouda Trutnov 0 10 20 30 40 50 60 171 175 548 554 557 558 Diameter (mm ) 171 175 548 554 557 558 Number of clone 0 50 100 150 200 250 300 350 400 171 175 548 554 557 558 Height (cm) Number of clone Lesní Bouda Trutnov Lesní bouda Trutnov Lesní bouda Trutnov J. FOR. SCI., 56, 2010 (7): 314–322 317 excellent growth of tree No. 171 in Lesní bouda ortet plantation. e growth of tree No. 548 is obviously worse compared to the other trees in Trutnov ortet plantation. A similar trend was observed in the clone planta- tion on Benecko RP (Figs. 3 and 4), where columns represent the average values of vegetative progenies (clones) of the above-described trees. All trees grow there in relatively identical conditions of one locality. Obviously, the growth of clone 171 is also very good in this locality while clone 548 is lagging behind. e analysis of variance for morphological traits and the values of chlorophyll fluorescence of trees growing on Černohorská rašelina RP indicates high statistical significance of the influence of provenance of particular variants (clones) (Table 2). Dispositions to the growth rate of particular clones were maintained to a large extent also in the 2 nd gen- eration clone plantation on Černohorská rašelina RP (Figs. 5 and 6). e evaluation of morphological traits of the clone plantation in this specific locality showed very good growth of some clones originally coming from this locality, especially of clone No. 171. e worst growth was observed in the progeny of clone No. 548 again. A comparison of the growth of rooted cuttings (2 nd generation clones) and control planting stock produced by a routine method shows the relatively good growth of generatively propagated plants for the time being. e health status (defoliation was not higher than 10% in any variant and there occurred hardly any changes in the coloration of assimilatory organs 2 years after outplanting) and growth dynam- ics of rooted cuttings were very good. is is the reason why we suppose that the favourable effect of the genetic quality of clone stock will be expressed over a longer period of growth in specific conditions similarly like in other experiments of ours. 250 300 0 50 100 150 200 250 171 175 548 554 557 558 Height (cm) a aabab b 171 175 548 554 557 558 Number of clone 35 40 ) 0 5 10 15 20 25 30 171 175 548 554 557 558 Diameter (mm ) a aab b b 171 175 548 554 557 558 Number of clone Fig. 4. Average stem diameter of vegetative progenies of spruce (1 st generation clones) in Benecko locality 9 years after outplanting – different letters in columns indicate statistically significant differences (5% significance level) Fig. 3. Average shoot height of vegetative progenies of spruce (1 st generation clones) in Benecko locality 9 years after out- planting – different letters in columns indicate statistically significant differences (5% significance level) 35 40 45 0 5 10 15 20 25 30 35 171 175 548 554 557 558 C Height (cm) a abab bc ab cbc 171 175 548 554 557 558 C Number of clone 10 12 0 2 4 6 8 171 175 548 554 557 558 C Diameter (mm) a abbb b cb 171 175 548 554 557 558 C Number of clone Fig. 5. Average shoot height of vegetative progenies of spruce (2 nd generation clones) in Černohorská rašelina locality 2 years after outplanting – different letters in columns indi - cate statistically significant differences (5% significance level), C – control Fig. 6. Average root collar diameter of vegetative progenies of spruce (2 nd generation clones) in Černohorská rašelina lo- cality 2 years after outplanting – different letters in columns indicate statistically significant differences (5% significance level), C – control 318 J. FOR. SCI., 56, 2010 (7): 314–322 Evaluation of the physiological state of spruce plants in the 2 nd generation clone plantation e physiological state of selected clone progenies was evaluated in the 2 nd generation clone plantation on Černohorská rašelina RP. Chlorophyll fluores- cence was measured in the spring season and the intensity of water losses was assessed in laboratory conditions in one-year shoots from the previous year. e evaluation of chlorophyll fluorescence shows the very good state and function of photosynthetic apparatus in rooted cuttings of all studied clones. e best values were measured in trees of clone 171 again. e results document very good adapta- tion of rooted cuttings to conditions of an extreme mountain locality. ey also indicate the better state of photosynthetic apparatus in comparison with control generative plants of the spruce mountain population (Fig. 7). e evaluation of water content in shoots after 15 and 180 minutes of controlled desiccation in laboratory conditions (Figs. 8 and 9) suggested the worse ability of trees of clone 548 to resist drought. On the contrary, the best-growing clone 171 was able to maintain a high water content during desiccation. e results of evaluation of the physiological state of the 2 nd generation rooted cuttings correspond to data on the growth of particular clones acquired in repeated in situ measurements. DISCUSSION Ortet and clone plantations were established in the last years mainly for the purposes of silvicultural research, i.e. successful artificial forest regeneration in extreme mountain conditions and formation of stable forest ecosystems. It is not a classical breeding programme that would allow using standard breed- ing methods of data processing. e objective was to acquire new knowledge essential for forest regenera- tion in extreme mountain locations. e results of field surveys showed the same re- lations in height and diameter growth among the studied clones in generative mother plantations and clone plantations of the 1 st and 2 nd generation. e higher growth dynamics of clones obtained from the best-quality trees with the best health status is a well-known fact (R 1977; E, J- 1988; I et al. 1995; S, A 2002; L et al. 2008) and the clone selection 0.60 0.62 0.64 0.66 0.68 0.70 0.72 0.74 0.76 0.78 0.80 171 175 548 554 557 558 C Fv/Fm Number of clone a bccc a bc ab Fig. 7. Maximal quantum yield of chlorophyll fluorescence F v /F m of needles of spruce samples from Černohorská rašelina RP – different letters in columns indicate statistically signifi- cant differences (5% significance level), C – control Table 4. Analysis of variance for the values of chlorophyll fluorescence F v /F m on Černohorská rašelina RP Sums of squares Degrees of freedom Mean squares F exp Variants (clones) Sa = 0.045 6 0.000713 15.438 Error Sr = 0.087 178 0.000471 Total Sc = 0.132 184 Conclusion of test: effect is statistically significant at the α = 0.05 level Table 3. Analysis of variance for shoot height on Černohorská rašelina RP Sums of squares Degrees of freedom Mean squares F exp Variants (clones) Sa = 14,889.2 6 245,319 11,159 Error Sr = 127,641.1 574 220,071 Total Sc = 142,530.3 580 Conclusion of test: effect is statistically significant at the α = 0.05 level F v /F m J. FOR. SCI., 56, 2010 (7): 314–322 319 in Norway spruce is used in forest operations to increase the production of vegetatively propagated planting stock. e growth of Norway spruce mountain popula- tions is rather different compared to populations from lower locations. Besides, the primary objective in extreme mountain conditions is not to ensure production but first of all to provide for the stabil- ity of forest ecosystems. Mountain populations of Norway spruce have lower growth rate compared to populations from lower locations (K 1998; O et al. 1998; U 1999; M, E 2002) and different growth rhythm (L 1989; W et al. 1999; H, W 2000; W et al. 2000b; M, E 2002). Earlier termination of elongation growth and bud formation are marked characteristics (H et al. 1987; M et al. 2006). Such growth dynamics is fixed genetically, and spruce seedlings maintain it at least in the first year of growth even though they are grown in completely different conditions (greenhouse, growth chamber) (H 1984; Q- et al. 1995). Adaptation to the adverse environment at the cost of growth is considered to be one of the main causes (O et al. 1998). In extreme mountain conditions the aim of plant- ing stock selection is not higher growth rate but it is the best adaptation to adverse environmental fac- tors. M and E (2002) reported higher resistance to drought in spruce populations originating from high altitudes above sea level com- pared to spruce from lower locations; their higher frost hardiness is also known (H, S 2000; W et al. 2000a). erefore progenies of trees best surviving and growing in these specific extreme conditions should be used for the reforesta- tion of extreme localities. e results of morphological surveys in our trials document good growth dynamics of the selected 2 nd generation clones. Although the differences in growth dynamics were not statistically significant in all cases, these findings are very interesting, con- firming a hypothesis that the selection of clones for extreme climatic conditions can be done through natural selection in mother plantations in exposed mountain localities (S et al. 1986). In our trials the study of the 2 nd generation clone plantations showed high variability of growth not only among the clones within one progeny but also within some clones. ree years after outplanting the influence of transplant shock was still visible in these extreme conditions. e influence of dif- ferences in microsites within one locality was also considerable. e observed large intraclonal differ- ences are consistent e.g. with data of J and S (1992), who observed high variability of growth within some clones of Norway spruce while other clones were homogeneous. W et al. (1999) reported that in the particular localities the conditions of small-area sites, i.e. soil conditions, in combination with large-area influences such as altitude contributed to the stress of trees. Based on detailed evaluation of a number of biochemical and physiological characteristics they found out that small-area soil influences, e.g. insufficient supply of water, could contribute to the overall stress of spruces in a crucial way. High sensitivity of young spruces to microsite conditions was reported by J (1999). Other authors also described a significant clone × site interaction in Norway spruce (I et al. 1995). K and H (1998) and K (2000) stated that the height growth of clones by site interaction often changed with the age of clone plantation. e selection of clones 50 60 70 80 90 100 Water content (%) 30 40 50 60 70 80 90 100 171 175 548 554 557 558 C Water content (%) Number of clone a babcabbcb 40 45 50 55 60 65 70 75 W ater content (%) 30 35 40 45 50 55 60 65 70 75 171 175 548 554 557 558 C Water content (%) Number of clone a babababcc ab Fig. 8. Water content in annual shoots after 15 minutes of desiccation in laboratory conditions (in % of the initial water content) – different letters in columns indicate statistically significant differences (5% significance level) Fig. 9. Water content in annual shoots after 180 minutes of desiccation in laboratory conditions (in % of the initial water content) – different letters in columns indicate statistically significant differences (5% significance level) 320 J. FOR. SCI., 56, 2010 (7): 314–322 propagated by cuttings according to their height in a nursery influenced the height of clones 6 years after outplanting to a small extent only (H 2003). I et al. (1995) also concluded that the height of cuttings in a nursery was not a reliable indicator of future development after outplanting. It is recom- mended to select clones older than 8 years for growth (G et al. 1991). A comparison of selected clones with the control planting stock of the Norway spruce population Krkonoše 3 years after outplanting indicated relatively good growth and physiological quality of generatively propagated plants, which is consistent with data reported by K (2003), who also compared the growth and health status of vegetatively and gen- eratively propagated planting stock of Norway spruce from the 7 th and 8 th forest altitudinal zone in the Krkonoše Mts. Genetic quality gained by vegetative propagation of high-quality spruce plants is not mostly expressed immediately after outplanting, which was documented e.g. by S and A (2002), who evaluated 5,000 spruce clones in Sweden and ascribed the large height increment of spruce clones compared to generative plants 6 years after outplant- ing, besides good genetic characteristics, to better characteristics of planting stock when rooted cuttings had thicker stems and were generally more robust than seedlings. Rooted cuttings on Černohorská rašelina RP had very good health status and growth dynamics. It is assumed that the favourable influence of genetic qual- ity will be expressed after a longer period of growth in specific conditions similarly like in other experiments of ours (J et al. 2005). Different dynamics of physiological processes is described in rooted cuttings compared to seedlings, e.g. later onset and lower intensity of dormancy and cold hardiness and earlier flushing in spring (F et al. 2000). e evaluation of the 2 nd ge- neration rooted cuttings in Černohorská rašelina re- search locality did not reveal any larger differences in the intensity of water losses between rooted cuttings and generatively propagated material. Certain diffe- rences observed among the clones corresponded to the growth rate of these clones. e measurement of chlorophyll fluorescence may provide detailed information on the photochemistry of photosystem II, which is sensitive to adverse environmental fac- tors such as strong light, low temperature, overheat- ing or drought (M, J 2000; K 2004; L et al. 2005). e values of maximal quantum yield of fluorescence measured in our clone plantation document the better state of photosynthetic apparatus in selected clones com- pared to control plants. CONCLUSION e study of the growth and vitality of selected clones in ortet and clone plantations brought about the following information: – Identical relations of growth among the studied clones were observed on research plots with ortet and clone plantations in different site conditions. In all localities the growth of clone No. 171, which represents dynamically growing clones in original generative mother planta- tions, was markedly the best. On the contrary, the clone that was selected as a representative of the lowest-quality clones in the generative ortet plantation was the worst again in all types of sites. Relatively good growth in the extreme mountain locality Černohorská rašelina was also observed 2 years after outplanting in the control (generative) planting stock of the spruce moun- tain population. – e above-mentioned differences in morpho- logical traits of clone plantations correspond to physiological characteristics studied in the 2 nd generation clone plantation. e maximal quantum yield of photosystem II photochemistry (F v /F m ) was measured in the best-growing clo- ne 171. is clone also had the lowest water loss- es during controlled desiccation. On the other hand, the worst-growing clone 548 had the least favourable values of these parameters. – The results of measurements of chlorophyll fluorescence and water losses during controlled desiccation indicated the better instantaneous physiological state of studied clones compared to the control plants of generative origin. ey con- firmed the better adaptation of selected clones of local provenance to the specific conditions of mountain locality. – e results illustrated very good growth dynam- ics of selected clones in extreme climatic condi- tions provided that cuttings were taken from vital parent trees growing in exposed mountain localities. e growth of the 2 nd generation clone plantation will require subsequent measurements in a longer time series in order to eliminate the potential influ- ence of transplant shock and of the clone growth by site conditions interaction. 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J L, Výzkumný ústav lesního hospodářství a myslivosti, v.v.i., Strnady, Výzkumná stanice Opočno, Na Olivě 550, 517 73 Opočno, Česká republika tel.: + 420 494 668 392, fax: + 420 494 668 393, e-mail: leugner@vulhmop.cz . in the framework of long-term programmes using the clonal propagation (J et al. 1994); their re- Evaluation of the growth and health status of selected clone mixtures in comparison with. exposed locations where their observation continues and their growth and health status are compared with the ordinary planting stock of generative origin. e objective of these experiments is. both the individuals with intensive growth dynamics and the slow-growing individuals were selected for a subsequent mixture of clones). After their growing in a nursery they were outplanted in